This season’s flu vaccine was 45% effective overall and 55% effective among children and teens, the Centers for Disease Control and Prevention reported in February.Doctor administering vaccine to child

In a Feb. 21 study in Morbidity and Mortality Weekly Report, researchers examined data from more than 4,100 children and adults enrolled in the U.S. Influenza Vaccine Effectiveness Network between October 2019 and January 2020. The interim findings showed that vaccine effectiveness was 25% among U.S. adults ages 18 to 49 and 43% among adults ages 50 and older.

While the results are consistent with previous years, researchers said lower rates among younger adults may be associated with trends showing lower vaccine effectiveness against influenza A subtype H1N1 within the age group — an issue CDC said it would continue to monitor.

Overall during the 2019-2020 flu season, the vaccine reduced doctor’s visits for flu illness by almost half, the study reported. Researchers said that decline is important considering prevalence of the disease. In the last decade, researchers noted, the flu resulted in upward of 21 million doctor visits, 810,000 hospitalizations and 61,000 deaths each year.

Continue reading this story from the May 2020 issue of The Nation's Health.

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